This proposal is for support of the Operations Office and four funded Standing Committees of the Childrens Cancer Study Group, of 28 major pediatric institutions collaborating in clinical investigations of childhood cancer. The Operations Office, under the direction of the Group Chairman, provides the Group with administration, communications, management and biostatistical analyses of Group data by manual and electronic processing methods. The funded Standing Committees include the Radiation Therapy, Surgical Steering, Pathology and Immunology Committees. These committees provide input to the Group with regard to protocol design, study conduct and data collection and evaluation. They are also responsible for developing Special Studies of a non-therapeutic nature in their respective areas.